Thesis

Biologically inspired acoustic systems : from insect ears to MEMS microphone structures

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Awarding institution
  • University of Strathclyde
Date of award
  • 2015
Thesis identifier
  • T14268
Person Identifier (Local)
  • 200991751
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Abstract
  • Although difficult to notice initially, examples of bioinspired technology have now become commonplace in society today. Construction materials, aerodynamic transport design, photography equipment and robot technology are among many research fields which have benefitted from studying evolution-driven solutions to common engineering problems. One field of engineering research which has recently begun to take inspiration from the natural world is that of acoustical systems such as microphones and loudspeakers. Specifically, to solve the problems involved in the miniaturisation of these systems, the auditory organs of insects are inspiring new design strategies. In this thesis, one such insect auditory system, that of the desert locust Schistocerca gregaria, was extensively studied beginning with a comprehensive review of the historical observations of the system. Micro-scanning laser Doppler vibrometry was then used to characterise the response of the locust ear, providing an explanation for the method behind frequency discrimination in the ear. Afterwards, finite element models, simulating the ear's features, were constructed with a view to furthering the understanding of each component of the hearing system. Directionality of the locust hearing system was also briefly investigated through computational modelling. All of these studies were performed with the overall aim of feeding into the future design of bioinspired acoustic sensors. Devices constructed using micro-electro-mechanical systems fabrication techniques, with similar dimensions to the ear of the parasitoid fly, Ormia ochracea, were then experimentally tested using laser vibrometry and simulated using finite element analysis. Although not originally designed to operate as such, one MEMS structure exhibited some element of mechanical directionality in its response, found to be both predictable and repeatable. The objective of this section of the PhD research was to test the hypothesis that any system with sufficient degrees of freedom is capable of displaying an element of directionality in its vibrational response.
Resource Type
DOI
Date Created
  • 2015
Former identifier
  • 1249406

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